A number of users have found that their multitouch trackpads on MacBook and MacBook Pro computers may randomly stop accepting 3 and 4 finger gestures. While two-finger scrolling, tapping, and clicking will work as expected, the more complex inputs do not seem to be recognized.This problem could be from a number of factors, including faulty preference files and other system settings and driver conflicts. Here are some tips and information that may help to tackle odd trackpad problems.Inherent trackpad delaysIf there are multiple confusing inputs being presented to the trackpad, the system may pause input for a second or two while it waits for a clear gesture to be used. These delays may be more prominent for multiple-touch gestures, so if you experience them, wait a few seconds and try the trackpad again with a firm and clear swipe instead of frantically trying to get the trackpad to work.Test the trackpadThe utility "BetterTouchTool" (available here) has a "Live View" feature that can be used to visualize trackpad inputs. After installing and launching the preferences (from the BetterTouchTool menu extra), if the trackpad driver is recognizing multiple inputs you should see the dots representing those inputs on the Live View display. Keep in mind the BetterTouchTool is very experimental at this point, and while it does work it may crash; however, this feature should let you know whether or not the trackpad and driver are still working.

BetterTouchTool Live View: After installing and opening, select the "Touchpad" tab and click "Show Live View" to see the finger inputs on the trackpad.(Credit: Screenshot by Topher)Change trackpad settingsIf the trackpad is not loading settings properly, try toggling some settings in the "Trackpad" system preferences. This should spur the system to load the new settings and hopefully get the trackpad working again.Remove third-party driversIf you have other input drivers, such as USB Overdrive, Logitech Control Center, or enhancers such as jiTouch or Multiclutch, try removing them and restarting the computer. Many times incompatibilities between input drivers may cause problems.Try removing the .GlobalPreferences.USER-UUID.plist fileThe user account's .GlobalPreferences file is a hidden preference file used for device settings such as colorsync profiles, default printers and monitors, and trackpad settings. After deleting this file and logging out and back in, you may need to ensure these items are setup correctly again. To do this, open the Terminal and follow these steps:Type the following command (do not press enter)rm ~/Library/Preferences/ByHost/.GlobalPreferencesPress the Tab key twice, and you should see an output of the files containing ".GlobalPreferences" in their name.Locate the one with the UUID in it (the UUID will look something like this: 6F77B0D6-8208-4977-8B45-EB1ADF6714BA) and start entering part of the UUID portion into the terminal so the command looks like the following:rm ~/Library/Preferences/ByHost/.GlobalPreferences.6F77BWhen you have entered part of the UUID section of the file name, press the Tab key once and the file name should automatically complete, so the command looks something like the following:rm ~/Library/Preferences/ByHost/.GlobalPreferences.6F77B0D6-8208-4977-8B45-EB1ADF6714BA.plistAfter the full filename has been typed, press enter to remove the preference file, and then log out and log back in to your user account.Reset the PRAMThe system's PRAM contains a number of settings, including those for mouse and trackpad input. Resetting the PRAM should clear any problematic settings that may interfere with the trackpad. To do this, reboot the system and immediately hold down the options-command-P-R keys. Hold the keys until the system resets a couple of times, and then release them and allow it to boot normally.

A few people have noticed Apple's new multitouch "Magic Mouse" will disconnect at seemingly random times. When the computer is booted the mice connect just fine and are usable for a while; however, they will soon become unresponsive and the "Connection Lost" icon will float at the bottom of the screen.When this happens, people have had mixed results with trying to get the mice reconnected. Some have claimed that just clicking the mice will get them to connect again, and others have mentioned tapping it on the case of their desktop computers was how they get it to connect.This problem appears to be with the mice losing power when movements jar the batteries slightly. In some cases people have been able to cause the mouse to disconnect by holding it up from the trackpad and firmly tapping on the top side of the mouse. This suggests that slight battery movement may cause the mice to lose power, and as such there are a couple of remedies available:Re-seat the batteries.If a small misalignment is causing the batteries to easily disconnect, try taking them out and putting them back in. This will exercise the spring mechanisms that hold the batteries in place, and perhaps cause them to apply a better hold on the batteries.Wedge paper under the batteries.Some people have had success in rolling up a small wad of paper and placing it between the batteries before closing the cover. This will put some additional pressure on the batteries to help secure them in place. If you do this, be sure you do not put so much paper that you warp the battery door.Replace the batteries.If your batteries are running low, the mouse may start behaving erratically and disconnecting. However, if this is the case the computer should report the battery level as being at critical levels, as long as you have installed the Magic Mouse driver software.Apple has a recently released knowledgebase article that covers a number of issues people are having with their bluetooth devices, including the Magic Mouse. Unfortunately, even though they mention random shut-offs, they only suggest checking battery levels and checking for interference as possible solution.

by Paul_31 December 30, 2009 8:21 AM PSTA fix for me was to make the Magic Mouse a 'favourite' in Bluetooth preferences. Since I did that I haven't lost a connection in over a month.Like thisReply to this commentby castaicmac December 30, 2009 9:25 AM PSTOn two iMacs, (early 2009 and late 2009) I've encountered "null" zones close (within 9 inches) to base of iMacs. Backing off a bit restores control. No "Connection Lost" prompt, however.Like thisReply to this commentby castaicmac December 30, 2009 5:22 PM PSTOn second thought, my "null" issue, appears to indeed be a surface based-issue. Changing my surface contact essentially makes the null point issue disappear when I eliminate discontinuities between surfaces upon which the mouse travels. So, never mind.Like this1 person likes this commentby tkessler December 31, 2009 2:43 PM PSTThat is a common problem that I think many people encounter but dismiss because Laser and optical mice these days are advertised as being usable on practically all surfaces, even glass.Like thisby MaxwellSmart27536 December 30, 2009 9:50 AM PSTI am using a "magic mouse" on a brand new Mac Pro, and it will lose the Bluetooth connection without touching the mouse at all. Besides eating batteries at the rate of two every five days, and being very erratic depending on what surface it's used on, this is not a very well engineered mouse.Like thisReply to this commentby BrianMarsh December 30, 2009 10:26 AM PSTSeems to be more of an issue with MacPro's and the mice, than the mice themselves.Customers purchased and display models of the iMac 21.5 & 27" still haven't gone through even one bar of the batteries.They are so backordered through the reseller channels in Canada that I haven't been able to purchase one for personal use yet to test with my MacPro or my wife's iMac

all optical mice can be erratic depending on the surface, in my somewhat limited testing of the new mice, they are doing better than the previous "Mighty Mouse" and more in line with the higher end logitech models (better than the cheap logitechs, not quite as good as their top end models)Like thisby Swift2 January 1, 2010 10:22 PM PSTI've got the 24" iMac, 9,1, and a Magic Mouse I bought instead of cursing Apple for bringing out the newer iMac so soon after I bought mine. I've got to say, as so often with MacFixit problems, I haven't had any troubles like this. I haven't had a Bluetooth mouse before, and I don't like the way it eats up batteries. A week and a half, and I'm down to 75%. At 20%, the big white shmear comes on the screen and it starts nagging me for new batteries. I'd say that's in about 6 weeks. Is that normal? Should I turn it off when I walk away? That's a pain in the behind, I must say. Otherwise, I love the thing.Like thisReply to this commentby tkessler January 2, 2010 1:26 AM PSTI have not had my magic mouse long enough to test this, but I will keep my eye on the battery usage. I've not turned it off much, and it's still at 100% battery after ~10 days of heavy usage. From that I'd say that your batteries are draining rather fast, however, it could be a matter of dead batteries to begin with. Have you tried new and reputable ones (Duracell or Energizer)?Like this